While weighing the options for replacing a small, low-slope,
porch hip roof, I quickly rejected half-lap, mineral-surfaced
roll roofing. It would have to be redone or coated in eight to
ten years, if not sooner. A bituminous underlayment, such as
Grace Ice & Water Shield, under standard three-tab asphalt
shingles would work, but only on slopes 2:12 and steeper.
There's always torch-down, but I don't do a lot of it, and I
don't own a torch. I didn't want the rental expense, not to
mention the risk of using an open flame on a combustible roof
surface. I was tempted to go with a top-of-the-line flat roof
product and sub the job out to a certified EPDM rubber membrane
installer. But I didn't need the scheduling hassles, and there
probably wouldn't be much money left in the end for my trouble
and headache.
What I needed was a durable, easy-to-install membrane that I
could handle myself, preferably one that didn't involve buckets
of the tenacious black stuff that has a way of getting on
everything, including your tools, hands, and the finished roof
surface.

Advantages of EPDM

A little research turned up WeatherBond 110 (WeatherBond Pro,
P.O. Box 2022, Mechanicsburg, PA 17055; 800/575-4406), a
45-mil, black EPDM rubber roofing membrane backed with 20-mil
butyl adhesive. Designed for smaller roofing jobs, it comes in
4x25-foot rolls that cover one square each. It has a
peel-and-stick release liner, slit lengthwise at 4 and 24
inches from one edge to facilitate installation.
Single-ply EPDM rubber roofing has many advantages over
other roofing options. It remains flexible at extreme
temperatures, can be installed quickly, and resists
deterioration from exposure to ultraviolet radiation -- a
protective coating, like natural stone, is not required as with
some torch-down products.
Expensive option. The rubber membrane is
expensive. The cost, including the EPDM roll, cover strip,
primer glue, and sealant is about $160 per square. And you need
to figure in some extra for corner covers and pipe boots. But
the installation cost fares pretty well compared to a
torch-down product, considering the labor and expense of
installing a UV coating over the torch-down. The WeatherBond
110 membrane is also available in solid white rubber, but it
costs about 16 percent more than the black rubber. White
reflects most of the sun's infrared rays, which helps to keep
the roof and the space below cool in warmer climates.
Currently, the same black cover strips must be used with the
white rubber membrane. It's possible to paint the black cover
strips, using acrylic latex or oil-based paint but successive
coats of paint may be necessary to prevent bleed-through.
However, the company plans to have a white cover strip
available this fall.
Warranty. The 12-year WeatherBond warranty is,
to date, the best I've found in the category of residential
low-slope roofing products. And, if the performance of
single-ply EPDM roofing on commercial installations is any
measure, WeatherBond 110 can certainly last much longer than 12
years, if it's properly installed. Granted, the product was a
little hard to find for this job. It was available at only one
roofing supplier in my area. WeatherBond's area rep assured me
that the company is encouraging lumber retailers to stock their
product, so its availability may improve.
Temperature range. WeatherBond 110 is best
installed at temperatures ranging between 40F and 80F. However,
there is some latitude. If it's 35F, but it's sunny on the
deck, the material may be workable enough. The same holds true
if it's 85F but cloudy. The glue on the product gets very
aggressive in high temperatures, and special techniques must be
used to install it (see "Helpful Hints," below). The
manufacturer provides an installation video and instruction
booklet, on request, that clearly illustrate these and other
procedures.

Helpful Hints

To minimize wrinkling and movement of
the installed membrane during
installation, lay down strips of
plywood
to walk on.

In cooler temperatures, the tack of the
adhesive decreases. Store the material
in a warm place prior to installation.

Use chemical-resistant gloves to
protect skin when applying primer.

Overlaps of the membrane should be a
minimum of 4
inches.

WeatherBond 110 cuts best with a
utility knife from the
top side.

Hot-Weather
Considerations

Use white primer for the roof surface to
reduce the temperature of the roof deck.

Keep the membrane in the shade until
needed.

Install the membrane early in the day when
the sun is
low on the horizon.

Use shorter lengths of membrane to limit
exposure and setup time.

Liner is more difficult to remove in hot
weather. Remove
it with abrupt tugs and hold the membrane
firmly to prevent adhesive from contacting
itself.

WeatherBond membranes are not compatible with uncured
petroleum-based materials, such as fibered aluminum roof
coatings. However, WeatherBond can be installed over cured
petroleum products, such as a fibered-aluminum-coated trailer
roof.
If I were doing a roof that was any larger than this one --
which was 12x26 feet -- I would seriously consider using
another product, WeatherBond 101, to eliminate a couple of the
time-consuming aspects of the job. WeatherBond 101 is a 60-mil
EPDM material that comes in 10x20-foot sheets. The sheets are
shipped folded in a box, rather than in rolls. The 101 is a
standard glue-down rubber membrane and has no self-adhesive
backing.

Roof Prep

WeatherBond 110 will adhere to a variety of surfaces,
including wood, metal, plastic, glass, fiberglass, rubber,
masonry, smooth-surfaced built-up roofs, and nongranular roll
roofing. For this reroof, I wanted to start with a good, clean
substrate, so I stripped the old asphalt roofing down to the
roof boards -- being careful to clean and preserve the existing
wall and chimney flashing -- and installed a layer of 1/2-inch
OSB, which I had coated with a good latex paint primer the day
before installation. The primer is recommended for better
adhesion of the WeatherBond butyl-adhesive backing to the wood.
I primed the sheets ahead of time so that I could strip and
protect the roof the same day.
After checking the surface for any protruding fasteners, I
cut 6-inch strips of the roofing material from the 4-foot roll
and installed them over the rough edges of the plywood hip to
cushion the membrane against premature wear (see Figure 1). I
figured this might be one of the first areas to develop a
problem.

Figure
1. Weatherbond 110 self-adhering EPDM must be
installed over a clean, paint-primed substrate. The
author paints OSB sheathing prior to installation in
order to speed the membrane installation. To protect
the membrane from wear over sharp corners, he installs
a 6-inch-wide strip of the membrane over the
transitions first

The starter course is partially rolled out for alignment,
overhanging the edge of the roof by about 1 1/2 inches. I made
a pencil mark on the deck where the center slit in the release
liner falls, marked that same measurement up from the edge at
the opposite end of the roof, and snapped a guideline for the
rollout. Aligning the center slit with the guideline, we rolled
out the roofing, simultaneously peeling back the 20-inch-wide
liner strip, leaving the 4-inch liner temporarily in place at
the bottom edge. After securing the lower half of the roll to
the roof, we slid the upper release liner out from the top and
smoothed the wrinkles out of the membrane with a push broom
(Figure 2).

Figure
2. The starter course overhangs the roof edge by
about 1 1/2 inches. A push broom is the ideal tool to
embed and smooth the membrane into place as the
protective paper facing is peeled away.

At the overhang, we pulled off the 4-inch release strip and
wrapped the membrane over the edge, nailing it to the fascia
every 6 inches. I folded the outside corners over and nailed
them.